标签：iostream ios 表示 相同 推导 operator 注意 存储 优先
一，函数模板
1.函数模板的概念
2.函数模板的推演
# include<iostream> using namespace std; /* 交换两个整数 */ void myswap(int &a, int &b) { int tmp = 0; tmp = a; a = b; b = tmp; } /* 交换两个字符 */ void myswap(char &a, char &b) { char tmp; tmp = a; a = b; b = tmp; } /* * 我们发现上面两个函数的实现逻辑结构相同，要处理的数据类型不同， * 而函数模板恰恰是将数据类型参数的一种机制，所以此处我们在这里定义函数模板 */ template<typename T> void myswap(T &t1, T &t2) { T tmp; tmp = t1; t1 = t2; t2 = tmp; } int main() { int a = 10; int b = 20; char c = ‘C‘; char d = ‘D‘; myswap(a, b); myswap(c, d); cout << "a = " << a << ",b = " << b << endl; cout << "c = " << c << ",d = " << d << endl; /* 函数模板方式来处理 */ myswap<int>(a, b); myswap<char>(c, d); cout << "a = " << a << ",b = " << b << endl; cout << "c = " << c << ",d = " << d << endl; return 0; }
3.函数模板的形式
在需要抽象化成模板的函数前面添加：template <typename T1,typename T2......>，在函数体内部要处理的数据类型定义为模板参数中的抽象数据类型即可。
4.函数模板的调用方式
5.普通函数和函数模板在一起时调用规则
6.C++编译器模板机制剖析
二，类模板
1.为什么需要类模板
类模板的含义与函数模板类似，所谓的类模板是在多个类中的逻辑操作和功能是相同的，仅仅数据的类型不同，我们将数据类型抽象化就形成了类模板。类模板通常用在数据结构和算法这一块，这样在存储数据和对数据进行操作的时候，可以抽象化要操作的数据。形成泛型编程。
2.单个类模板的语法
# include<iostream> using namespace std; /* 定义类模板 */ template<typename T> class A { private: T t; public: A(T t) { this->t = t; } void setT(T t) { this->t = t; } T getT() { return this->t; } }; int main() { A<int> a(10); int res1 = a.getT(); cout << res1 << endl; a.setT(200); int res2 = a.getT(); cout << res2 << endl; return 0; }
3.继承中的类模板
# include<iostream> using namespace std; /* 类模板 */ template<typename T> class Parent { private: T t; public: Parent(T t) { this->t = t; } void getT() { cout << t << endl; } }; /* 类模板继承中的子类为普通类 */ class Child1 :public Parent<int> { public: Child1(int t):Parent(t) { } }; /* 类模板中继承的子类为类模板 */ template<typename T> class Child2 :public Parent<T> { public: Child2(T t) :Parent(t) { } }; int main() { /* 子类为普通类 */ Child1 c1(10); c1.getT(); /* 子类为派生类 */ Child2<char> c2(‘A‘); c2.getT(); return 0; }
4.类模板的定义和类模板的实现不在同一个文件中
三，类模板的应用
1.头文件（Vector.h）
# pragma once # include<iostream> using namespace std; template<typename T> class Vector { private: T * space; int size; public: Vector(int size = 0); Vector(const Vector<T>& v); ~Vector(); public: T& operator[](int index); Vector<T>& operator=(Vector<T>& v); public: friend ostream& operator<<<T>(ostream& out, Vector<T>& v); };
2.实现文件（Vector.cpp）
# include<iostream> # include"Vector.h" using namespace std; template<typename T> Vector<T>::Vector(int size) { this->space = new T[size]; this->size = size; } template<typename T> Vector<T>::Vector(const Vector<T>& v) { this->space = new T[v.size]; this->size = v.size; for (int i = 0; i < v.size; i++) { this->space[i] = v.space[i]; } } template<typename T> Vector<T>::~Vector() { if (this->space != NULL) { delete[] this->space; this->space = NULL; this->size = 0; } } template<typename T> T& Vector<T>::operator[](int index) { return this->space[index]; } template<typename T> Vector<T>& Vector<T>::operator=(Vector<T>& v) { if (this->space != NULL) { delete[] this->space; this->space = NULL; this->size = 0; } this->space = new T[v.size]; this->size = v.size; for (int i = 0; i < v.size; i++) { this->space[i] = v.space[i]; } return *this; } template<typename T> ostream& operator<<(ostream& out, Vector<T>& v) { for (int i = 0; i < v.size; i++) { out << v[i] << " "; } return out; }
3.测试文件(Test.cpp)
# include<iostream> # include"Vector.cpp" using namespace std; class Student { private: char * name; int age; public: Student() { this->name = new char[1]; strcpy(this->name, ""); this->age = 0; } Student(const Student& stu) { this->name = new char[strlen(name) + 1]; strcpy(this->name, name); this->age = age; } Student(char * name, int age) { this->name = new char[strlen(name) + 1]; strcpy(this->name, name); this->age = age; } ~Student() { if (this->name != NULL) { delete[] this->name; this->name = NULL; } } Student& operator=(Student& stu) { if (this->name != NULL) { delete[] this->name; this->name = NULL; } this->name = new char[strlen(stu.name) + 1]; strcpy(this->name, stu.name); this->age = stu.age; return *this; } friend ostream& operator<<(ostream& cout, Student& stu); }; ostream& operator<<(ostream& cout, Student& stu) { cout << "name:" << stu.name << ",age:" << stu.age << endl; return cout; } int main() { Vector<int> v1(10); for (int i = 0; i < 10; i++) { v1[i] = i; } cout << v1 << endl; Vector<int> v2(5); for (int i = 0; i < 5; i++) { v2[i] = i; } cout << v2 << endl; v1 = v2; cout << v1 << endl; Vector<int> v3 = v1; cout << v3 << endl; Student t1("刘备", 49); Student t2("关羽", 38); Student t3("张飞", 34); Vector<Student> vTeacher(3); vTeacher[0] = t1; vTeacher[1] = t2; vTeacher[2] = t3; cout << vTeacher << endl; return 0; }
标签：iostream ios 表示 相同 推导 operator 注意 存储 优先
原文地址：http://www.cnblogs.com/metalsteel/p/6285766.html
